The invention relates to a method for heat treatment of a disc, whereby the disc is placed on a carrier after which the disc is irradiated.
The invention also relates to a device for heat treatment of a disc according to said method.
By such a method and device, which are known from the international patent application WO 97/36738 a disc comprising two disc elements with an adhesive layer between them, is placed on a carrier after which the disc is irradiated by UV light and the adhesive layer is cured.
The UV light will also heat up the carrier and when a new disc is placed on the carrier, the disc will be warped due to the temperature difference which occurs between the disc element located on the carrier and the other disc element. The time between placing the disc onto the carrier and the irradiation of the disc is too short to stabilize the temperature of the disc. It is an object of the invention to provide a method whereby undesired warping of the disc is avoided.
This object is achieved in that during the irradiation the carrier is kept on a desired temperature.
By controlling the temperature of the carrier, the warping of the disc can also be controlled.
In a preferred embodiment of the method according to the invention the desired temperature of the carrier is about the temperature of the disc prior to placement on the carrier.
In this way the disc will not be subjected to a change of temperature.
If, however, a certain controlled warp is desired, for example to have a compensation for a tilt during a later process step, the temperature of the carrier is kept at another predetermined value.
In another preferred embodiment a method according to the invention the disc comprises two disc elements and an adhesive layer between the disc elements, whereby the adhesive layer is cured by the irradiation with ultraviolet light.
Due to the vacuum the disc is kept flat against the carrier. Furthermore a good contact between the disc and the carrier is obtained due to which the heat transfer function is the same all across the disc.